JP2003035992A - Cylindrical developer carrying member and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical developer carrying member by which toners are sufficiently electrostatic charged on a developing sleeve after the repetitive use and can be deposited and conveyed as a uniform layer free of deflection and the occurrence of a difference in developing capability meeting a development history can be averted. SOLUTION: This cylindrical developer carrying member has an anodized aluminum layer with which a conductive substrate surface uniformly subjected to surface roughening is coated; said anodized aluminum layer having micropores reaching the substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical developer carrying member mounted in an electrophotographic apparatus such as an electrophotographic printer, a copying machine and a facsimile.

[0002]

2. Description of the Related Art Electrophotographic devices such as laser printers, LED printers and plain paper copying machines form images by the so-called Carlson process. The Carlson process is a cycle of an electrophotographic process using a member such as charging, exposure, toner development, transfer, and charge removal arranged on the peripheral surface of a cylindrical photosensitive member having a photosensitive layer having a photoconductive function. It is an image forming method of outputting by fixing the toner image transferred to.

In this process, when the electrostatic latent image formed on the surface of the photosensitive member by the charging and exposure is visualized by the next toner development, the toner in the developing device is cylindrical. The latent image on the surface of the photoconductor is developed by being carried and conveyed in the vicinity of the surface of the photoconductor by using electrostatic force through a developer carrier, that is, a developing sleeve. In order to obtain a good image by such a developing method, it is extremely important that the toner on the developing sleeve is carried and carried as a uniform layer on the developing sleeve without unevenness.

Further, if the toner layer on the developing sleeve is too thick or too thin, a good image cannot be expected in terms of developing density. For this reason, although it is necessary to separately provide a member for controlling the thickness of the toner on the developing sleeve, the surface condition thereof is also important for evenly distributing the toner on the surface of the developing sleeve. As such a surface state, a smooth surface is not necessarily the best, and it is said that it is better to provide unevenness of an appropriate size so as to provide an appropriate frictional force between the sleeve and the toner. However, this unevenness is
Depending on the hardness of the developing sleeve material, there is a problem that after repeated use, the material wears and the image gradually deteriorates. Therefore, improvement in abrasion resistance is required. When the developing sleeve material is aluminum alloy, its Vickers hardness is about 70.
Since it is as small as Hv, it is known that after forming irregularities on the surface, forming an alumite surface layer by anodic oxidation having a large Vickers hardness of about 200 Hv to 400 Hv improves abrasion resistance (Japanese Patent Laid-Open No. 5-46008). reference).

On the other hand, when an alumite layer is provided on the surface of the developing sleeve, the surface resistance becomes high due to the insulating property of the alumite layer. However, if the surface resistance is high, the electric charge of the toner in the portion corresponding to the image forming portion in the previous developing process tends to remain without being sufficiently moved from the developing sleeve side to the photoreceptor surface side, and The charge amount of the image forming corresponding portion becomes larger than the charge amount of the non-image forming corresponding portion. Then, in the image formation corresponding portion, when a new image is formed in the next development process, the developer is more strongly attracted to the portion of the developing sleeve having a high charge amount, and it becomes difficult to move to the surface side of the photoconductor. As a result, the developed image on the photoconductor side has a density difference having a pattern corresponding to the image in the previous development process, that is, a so-called ghost image (in summary, the difference in developing ability depending on the development history-the following: In the invention, it is also called a memory).

[0006]

In view of the problems described above, in the present invention, the toner is sufficiently triboelectrically charged on the developing sleeve even after repeated use, and is carried and carried as a uniform layer without deviation. It is an object of the present invention to provide a cylindrical developer carrying member that can be formed and does not cause a difference in developing ability depending on the development history, and a method for producing the same.

[0007]

According to the invention of claim 1, there is provided an alumite layer coated on the surface of a uniformly roughened conductive substrate, the alumite layer reaching the substrate. The above object can be achieved by using a cylindrical developer carrying member having uniform holes.

According to the second aspect of the invention, it is preferable that the conductive substrate is the cylindrical developer carrier according to the first aspect, which is mainly composed of an aluminum-based metal material.

According to the third aspect of the invention, it is more preferable to use the cylindrical developer carrying member according to the first or second aspect, wherein the alumite layer is an alumite layer formed by an anodic oxidation method.

According to the invention described in claim 4, the cylindrical developer carrying member according to any one of claims 1 to 3, wherein the alumite layer is a nickel acetate-sealed alumite layer. desirable.

According to the invention described in claim 5, it is more preferable that the cylindrical developer carrying member according to any one of claims 1 to 4 has a thickness of the alumite layer of 2 to 5 μm. .

According to the invention of claim 6, the cylindrical developer carrying member according to any one of claims 1 to 4, wherein the fine pores have an area of 10 to 50% of the alumite layer forming region. Is more desirable.

According to the invention of claim 7, the surface of the conductive substrate is uniformly roughened by the blasting treatment with the spherical fine particles to form an alumite layer by anodic oxidation, and then the diameter is larger than the spherical fine particles. It is suitable to use a method for producing a cylindrical developer carrying member, in which a blast treatment is carried out with amorphous particles.

According to the invention described in claim 8, after the blasting treatment of the surface of the conductive substrate using glass beads as the spherical fine particles to form an alumite layer by anodic oxidation, the diameter of the spherical fine particles is larger than that of the spherical fine particles. It is more appropriate to use the method for producing a cylindrical developer carrying member according to claim 7, wherein the blasting treatment is carried out by using non-uniform fine particles containing aluminum oxide as a main component.

According to the ninth aspect of the invention, the average surface roughness Ra = 0.8 to 1.5 is obtained by blasting the surface of the conductive substrate using glass beads as the spherical fine particles.
9. The cylindrical developer carrying member according to claim 7, wherein irregularities of .mu.m are provided and an alumite layer is formed by anodic oxidation, and then blasting is carried out with amorphous fine particles mainly containing aluminum oxide having a diameter larger than that of the spherical fine particles. Is more appropriate.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Specific examples of the cylindrical developer carrying member according to the present invention will be described in detail below with reference to the drawings. The present invention is not limited to the embodiments described below.

FIG. 1 is a perspective view of a cylindrical developer carrier, that is, a developing sleeve 11 according to the present invention, FIG. 2 is a partially enlarged sectional view of the developing sleeve 11, and FIG. 3 is a sectional view of the developing sleeve 11 according to the present invention. FIG. 1 is a schematic configuration diagram of an image forming apparatus 100 to be mounted, including a roller charging member 3, an exposure source 4, a developing device including a developing container 5 and a developing sleeve 11 on an outer peripheral surface of a photoconductor 10, a transfer device 6, a charge eliminating device 7, and the like. The electrophotographic process member of FIG.

An image forming apparatus 100 using the contact (roller) charging method shown in FIG.
An electrophotographic process is sequentially carried out by the members arranged on the peripheral surface of to form an image. In this image forming method, first, a voltage is applied to the roller charging member 3 arranged in contact with the electrophotographic photosensitive member 10 to charge the surface of the photosensitive member 10 and an image corresponding to the original is formed by the image exposing unit 4. The photoconductor 10 is imagewise exposed to form an electrostatic latent image. next,
The charged toner agitated in the developing container 5 is charged to the photoreceptor 10
The electrostatic latent image on the photoconductor 10 is developed (visualized) by electrostatically transferring and adhering to the surface via the developing sleeve 11. Further, the toner image formed on the photoconductor 10 is transferred onto the transfer material such as paper supplied through the paper feed roller and the paper feed guide by the transfer charger 6, and is not transferred to the transfer material by the cleaner, so that the photoconductor The residual toner remaining on 10 is collected. If residual charges remain inside the photoconductor, it is preferable to apply an appropriate voltage to the photoconductor 10 by the charge removal unit 7 to perform charge removal or charge removal using light. On the other hand, the transfer material on which the toner image has been formed is sent to a fixing device (not shown) by the conveying section to fix the toner image and output as an image.

In the image forming apparatus 100, the light source of the image exposing means 4 may be halogen light, fluorescent light, laser light or the like. Also, other auxiliary processes may be added if necessary. The image forming apparatus 100 can be widely applied to electrophotographic application fields such as a laser beam printer and an electrophotographic plate making system as well as a copying machine.

Incidentally, the developing sleeve 1 according to the present invention.
As shown in the perspective view of FIG. 1, reference numeral 1 has a sleeve-shaped conductive substrate 1 having a diameter of 20 mm and shaft-supporting portions provided on both sides thereof, and an aluminum alloy is used as the material. This diameter may be appropriately changed depending on the mounted device. Usually, the diameter is often in the range of 10 to 25 mm. In this example, the composition of the alloy was JIS A6063 material, but A5056 material and 3003 material may be used. The surface of the aluminum sleeve base 1 is made smooth by cutting or grinding the surface of a blank tube formed by extrusion and drawing of an aluminum alloy ingot with a cutting tool or a grindstone. Next, average particle size 4
The surface of the sleeve substrate 1 is blasted using spherical glass beads of 4 μm or less (# 600) to make the average surface roughness Ra 0.8 to 1.5 μm. If the average roughness is larger than 1.5 μm, the toner will remain in the concave and convex portions, and if it is smaller than 0.8 μm, it will be too smooth, and the triboelectric charging of the toner will be insufficient and the toner concentration will be insufficient. There is a problem that a high image density cannot be obtained. Further, there is a problem that the toner slips and the toner layer is apt to be biased, and it is difficult to form a uniform layer.

Next, the alumite layer 2 is formed on the surface of the sleeve substrate 1 on which the irregularities of a predetermined size are formed by the anodizing method, and a sealing treatment is performed. The sealing treatment is preferably nickel acetate sealing, but other sealing treatments also have the effect of the present invention. The layer thickness of the alumite layer is preferably in the range of 2 to 5 μm. If it is thicker than 5 μm, it becomes difficult to form a large number of fine holes 21 reaching the aluminum substrate 1 according to the present invention uniformly. If the thickness is less than 2 μm, the alumite layer will wear quickly and the durability will deteriorate.

The formation of the fine pores 21 after the formation of the alumite layer 2 is carried out by blast treatment of amorphous aluminum oxide (alumina) fine particles having a hardness higher than that of alumite. Fine particles of other materials may be used as long as they are harder than alumite. Further, as the particle diameter of the alumina fine particles, a particle diameter (for example, # 320) larger than that of the above-described glass beads (for example, # 600) is used. The purpose of the blasting treatment after the formation of the alumite layer 2 is to remove only the alumite layer 2 on the convex portion of the alumite layer 2 having irregularities as much as possible, and to provide an infinite number of fine pores 21 reaching the aluminum substrate 1 to form a toner By providing a large number of charge leakage sites evenly, the surface resistance of the alumite layer 2 can be reduced, and the problem of the difference in developing ability depending on the development history described above can be solved.

[0023]

[Experimental Example] The following experiment was conducted in order to obtain an appropriate area ratio of the micropores formed mainly in the convex portions of the irregularities of the alumite layer 2 to the entire alumite layer 2 formation region.

The total area ratio of the fine holes 21 to the alumite layer 2 region is 5%, 10%, 20%, 40%, 50%,
The developing sleeve 11 samples of 60%, 70%, and 100% were prepared, and the image evaluation and the life of the sleeve were examined.

The total micropore area ratio was determined by utilizing the difference in light reflectance between the alumite layer 2 region and the micropore 21. Specifically, using a light reflectometer, it was determined from a calibration curve prepared from a previously known sample. Alternatively, the area ratio may be obtained from an enlarged photograph of the sleeve surface. The results are shown in the table below.

The image densities were measured by a Macbeth densitometer, and those having a density of 1.3 or more were evaluated as ◯, those having a density of 1.2 to 1.3 were evaluated as Δ, and those of 1.2 or less were evaluated as x. From this image density evaluation, it can be seen that the toner is sufficiently tribo-charged on the developing sleeve and is carried and carried as a uniform layer without deviation.

In the image memory, no occurrence was indicated by O, slight occurrence was indicated by Δ, and occurrence was indicated by X. From this image memory evaluation, it can be seen whether the developing sleeve is in a surface state having an appropriate leak site that does not cause a difference in developing ability according to the development history.

The life of the sleeve is represented by ∘: durability of 20,000 sheets or more, ◯: 10,000 to 20,000 sheets, Δ: 10,000 sheets or less. From this life, the presence or absence of the change (or deterioration) of the characteristics in the initial two and after the repeated use of the predetermined number of sheets can be known in the two evaluations. In the overall evaluation, all three items are evaluated as ○, and even if there is one ×, the overall evaluation is also ×, and △ is evaluated, but ×
The overall evaluation of those that did not have a score was Δ.

[0029]

[Table 1]

From the above table, when the ratio of the area of fine pores according to the present invention to the alumite layer region on the surface of the developing sleeve is 10 to 50%, all three items are evaluated as ◯ and the overall evaluation is also ◯. Is clear.

[0031]

According to the present invention, a cylindrical developer having an alumite layer coated on the surface of a uniformly roughened conductive substrate and having fine pores reaching the substrate uniformly. Since it is a support, even after repeated use,
Provided is a cylindrical developer carrying member in which toner is sufficiently triboelectrically charged on a developing sleeve, can be carried and carried as a uniform layer having no deviation, and there is no difference in developing ability according to the development history. it can.

[Brief description of drawings]

FIG. 1 is a perspective view of a developer carrier according to the present invention.

FIG. 2 is a partially enlarged sectional view of a developer carrying member according to the present invention.

FIG. 3 is a schematic configuration diagram of an image forming apparatus equipped with a developer carrier according to the present invention.

[Explanation of symbols]

1 Conductive substrate (sleeve substrate) 2 alumite layer 21 Fine holes 10 photoconductor 11 Cylindrical developer carrier 100 image forming apparatus

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16C 13/00 F16C 13/00 EF term (reference) 2H077 AD06 AE04 FA00 FA03 FA14 FA16 FA26 3J103 AA02 AA51 AA61 EA20 FA18 GA57 GA58 GA60 HA18 HA37 HA54 HA60

Claims (9)

[Claims] 1. A cylindrical developer carrier comprising an alumite layer coated on the surface of a uniformly roughened conductive substrate, the alumite layer being uniformly provided with micropores reaching the substrate. body. 2. The cylindrical developer carrying member according to claim 1, wherein the conductive substrate is mainly made of an aluminum-based metal material. 3. The cylindrical developer carrying member according to claim 1, wherein the alumite layer is an alumite layer formed by an anodic oxidation method. 4. The alumite layer is a nickel acetate-sealed alumite layer.
The cylindrical developer carrying member according to any one of 1. 5. The cylindrical developer carrying member according to claim 1, wherein the alumite layer has a thickness of 2 to 5 μm. 6. The cylindrical developer carrying member according to claim 1, wherein the fine pores reaching the substrate have an area of 10 to 50% of the alumite layer forming region. 7. The surface of the conductive substrate is roughened by blasting with spherical fine particles to form an alumite layer by anodic oxidation, and then blasting is performed with atypical fine particles having a diameter larger than that of the spherical fine particles. A method for manufacturing a cylindrical developer carrying member. 8. An amorphous form containing aluminum oxide as a main component having a diameter larger than that of the spherical fine particles after blasting the surface of the conductive substrate using glass beads as the spherical fine particles to form an alumite layer by anodic oxidation. The method for producing a cylindrical developer carrying member according to claim 7, wherein blasting treatment is performed with fine particles. 9. An average surface roughness R is obtained by blasting the surface of a conductive substrate using glass beads as spherical fine particles.
a = 0.8 to 1.5 μm of unevenness is formed, an alumite layer is formed by anodic oxidation, and then blasting is performed with amorphous particles whose main component is aluminum oxide having a diameter larger than that of the spherical particles. The method for manufacturing a cylindrical developer carrier according to claim 7 or 8.